Qualification: 
M.Tech, B-Tech
greeshmasarath@am.amrita.edu

Greeshma Sarath currently serves as the Assistant Professor (Sr. Gr.) at the Department of Computer Science Engineering at Amrita School of Engineering, Amritapuri. Her research interests include Cryptography, Data Structures, Operating System. Greeshma has pursued an M. Tech. in Computer Science with a Gold Medal from NIT, Surat.

Publications

Publication Type: Conference Paper

Year of Conference Title

2016

B. Venugopal and Greeshma Sarath, “A Novel Approach for Preserving Numerical Ordering in Encrypted Data”, in 2016 International Conference on Information Technology (ICIT), Bhubaneswar, India, 2016.[Abstract]


Encryption of sensitive data is commonly used to preserve confidentiality and integrity. The problem with encrypting data is we have to decrypt it for applying operations on files such as altering a word document or querying a statistical database containing financial data. Decrypting the data will leave it vulnerable. If we want to perform conditional based search queries in an encrypted data entire data should be decrypted to perform it, unless an order preserving scheme is used. There is no homomorphic encryption scheme which will allow us to perform conditional based queries without decrypting the entire data. In mathematical term homomorphic describes the changeover of one data set into another upholding the association between elements in both sets. Order Preserving Encryption (OPE) schemes are used extensively used in cryptography because of their usage in database design. But there is a chances of inference attack in case of OPE. In this paper we had proposed and implemented a technique which will allow to perform conditional based search queries in the data encrypted using any encryption algorithm with log(n) decryption, thereby reducing complexity.

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2015

Greeshma Sarath and Jayapriya, R., “Securing Database Server Using Homomorphic Encryption and Re-encryption”, in 3rd International Symposium on Security in Computing and Communications, SSCC 2015, Cham, 2015.[Abstract]


A problem with organizations for shifting their storage to cloud or remote server is maintenance of confidentiality, integrity and availability of outsourced data,especially if the remote server is not trusted. Encryption can be used as a solution to these security concerns. But it should be possible for the data owner and other authenticated users of the data to perform queries (especially statistical queries) over data in encrypted domain. Usage of symmetric encryption will create another security concerns like management of key, denying a user from querying data etc. The problem with asymmetric encryption technique is only owner of the data is allowed to decrypt the data with his private key.

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2015

Greeshma Sarath and S.H, M. Lal, “Privacy Preservation and Content Protection in Location Based Queries”, in Proceedings of the 2015 Eighth International Conference on Contemporary Computing (IC3), Washington, DC, USA, 2015.[Abstract]


Location based services are widely used to access location information such as nearest ATMs and hospitals. These services are accessed by sending location queries containing user's current location to the Location based service(LBS) server. LBS server can retrieve the the current location of user from this query and misuse it, threatening his privacy. In security critical application like defense, protecting location privacy of authorized users is a critical issue. This paper describes the design and implementation of a solution to this privacy problem, which provides location privacy to authorized users and preserve confidentiality of data in LBS server. Our solution is a two stage approach, where first stage is based on Oblivious transfer and second stage is based on Private information Retrieval. Here the whole service area is divided into cells and location information of each cell is stored in the server in encrypted form. The user who wants to retrieve location information will create a clocking region(a subset of service area), containing his current location and generate a query embedding it. Server can only identify the user is somewhere in this clocking region, so user's security can be improved by increasing the size of the clocking region. Even if the server sends the location information of all the cells in the clocking region, user can decrypt service information only for the user's exact location, so confidentiality of server data will be preserved.

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Publication Type: Conference Proceedings

Year of Conference Title

2014

Greeshma Sarath, Deepu, S., Sundararajan, S., and Achuthan, K., “ESEC: An Ideal Secret Sharing Scheme”, Proceedings of ICCD 2014, 1st International Conference on Intelligent Computing, Communication and Devices, AISC, vol. 308 . Springer Advances in Intelligent Systems and Computing, pp. 135–143, 2014.[Abstract]


Secret sharing techniques have been used to ensure data confidentiality and enable secure reconstruction of data. In this paper, we propose a novel secret sharing scheme called ESEC based on Elliptic Curve Cryptography (ECC). The proposed scheme is to distribute a secret to a non-intersecting group of participants with different privilege levels. In our implementation, we have three phases involving share generation, distribution, and secret regeneration. The threshold of different privilege levels is different and for reconstruction of the secret all participants will have to be from the same privilege level. The proposed scheme is a perfect and ideal secret sharing scheme.

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